Eat

Gluten free, dairy free, casine free, wheat free, yeast free, additive/colours/preservatives/sugar free - yes, we did them all and got the t-shirt to prove it!
No, seriously, we cut out as much of the processed foods as possible, stuck to the gluten and dairy free diet for a number of years - before it was fashionable and we had the choice of cardboard or cardboard with tomato sauce at 10 times the price of 'normal' food - and yes, it worked.
For a while.